1. Field of the Invention
The present invention relates to the field of liquid crystal displaying, and in particular to a backlight module and a liquid crystal display device using the backlight module.
2. The Related Arts
A liquid crystal display device comprises a display module. To display an image with the display module, backlighting serving as a light source is needed. The backlight light source that is conventionally used comprises CCFL (Cold Cathode Fluorescent Lamp) and LED (Light-Emitting Diode). Currently, LEDs are used as a novel light source, which shows the advantages of high brightness and low power consumption. Consequently, the LED backlighting is getting prevailing and is considered a trend of future design. However, LEDs also generate a large amount of heat. To ensure the light emission efficiency and the lifespan of the LEDs, an arrangement of heat dissipation must be provided for the LEDs.
The currently adopted heat dissipation solution generally comprises backplane heat dissipation and aluminum extrusion (which is a heat dissipation structure formed through extruding aluminum) heat dissipation. The backplane heat dissipation requires a backplane to be entirely made of aluminum or an aluminum alloy and is thus of high cost, making it opposite to a design requirement of low cost, so that it is not commonly adopted. As shown in FIG. 3, aluminum extrusion heat dissipation refers to packaging LEDs 7 on a MCPCB (Metal Core Printed Circuit Board) to form an LED light bar and bonding the LED light bar to an aluminum extrusion 8 by thermally conductive adhesives, with the aluminum extrusion 8 being positioned on a backplane 9. A backlight module having such a structure suffers the following disadvantages:
(1) Packaging must be carried out on the LEDs and the MCPCB in order to make a light bar and additional operation is needed to bond the light bar to the aluminum extrusion 8; this costs working hours and materials.
(2) Structure is complicated, making thermal resistance interfaces increased and thus adverse to enhancement of heat dissipation performance.